Android: Do not build any extensions code except for extensions_constants.

extensions/extensions.gyp

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 80 matching lines @@
         'common/event_filter.cc',
         'common/event_filter.h',
         'common/event_filtering_info.cc',
         'common/event_filtering_info.h',
         'common/event_matcher.cc',
         'common/event_matcher.h',
         'common/extension.cc',
         'common/extension.h',
         'common/extension_api.cc',
         'common/extension_api.h',
-        'common/extension_api_stub.cc',
         'common/extension_icon_set.cc',
         'common/extension_icon_set.h',
         'common/extension_l10n_util.cc',
         'common/extension_l10n_util.h',
         'common/extension_message_generator.cc',
         'common/extension_message_generator.h',
         'common/extension_messages.cc',
         'common/extension_messages.h',
         'common/extension_paths.cc',
         'common/extension_paths.h',
@@ skipping 148 matching lines @@
       'msvs_disabled_warnings': [ 4267, ],
       'conditions': [
         ['enable_extensions==1', {
           'dependencies': [
             'common/api/api.gyp:extensions_api',
             '../device/bluetooth/bluetooth.gyp:device_bluetooth',
             # For Mojo generated headers for generated_api.cc.
             '../device/serial/serial.gyp:device_serial_mojo',
             '../device/usb/usb.gyp:device_usb',
           ],
-          'sources!': [
-            'common/extension_api_stub.cc',
-          ],
         }, {  # enable_extensions == 0
           'sources!': [
             'common/api/bluetooth/bluetooth_manifest_data.cc',
             'common/api/bluetooth/bluetooth_manifest_data.h',
             'common/api/bluetooth/bluetooth_manifest_handler.cc',
             'common/api/bluetooth/bluetooth_manifest_handler.h',
             'common/api/bluetooth/bluetooth_manifest_permission.cc',
             'common/api/bluetooth/bluetooth_manifest_permission.h',
             'common/api/messaging/message.h',
             'common/api/sockets/sockets_manifest_data.cc',
@@ skipping 945 matching lines @@
       'conditions': [
         ['OS=="win" and win_use_allocator_shim==1', {
           'dependencies': [
             '../base/allocator/allocator.gyp:allocator',
           ],
         }],
       ],
     },
   ]
 }